﻿using System;
using System.Collections.Generic;
using System.Text;

namespace CSharpLearn
{
    public class round
    {
        private double r;
        const  double PI = 3.14;

        public round()
        {
            Console.WriteLine("空参构造器");
        }
        public round(double r)
        {
            this.r = r;
        }
        public double getS( )
        {
            return r * r* PI;
        }
        public double getL()
        {
            return 2 * r * PI;
        }
        

    }
}
